Description

The ALSTOM IR139-1 is a critical component within the Microtrip family of protective relays, representing the legacy and expertise of ALSTOM (now part of the GE Grid Solutions portfolio) in electrical network protection. This specific model is a dedicated, single-phase instantaneous overcurrent and earth fault relay, designed to provide rapid and reliable detection of electrical faults in industrial and utility power systems. The primary function of the ALSTOM IR139-1 is to monitor current levels and instantly initiate a trip signal to a circuit breaker when a predefined current threshold is exceeded, thereby isolating faulty sections and preventing damage to expensive equipment like transformers, motors, and cables. Its simple yet robust design philosophy makes it an ideal choice for applications where dependable, standalone protection is paramount.

As a member of the well-regarded Microtrip series, the ALSTOM IR139-1 is characterized by its electromechanical design, ensuring operational security even in the harshest electromagnetic environments and in the absence of an auxiliary power supply. This self-powered operation is a key advantage, as the relay derives its energy directly from the current transformer (CT) signals, guaranteeing functionality during fault conditions. The relay’s time-instantaneous operation means it acts without intentional time delay, offering high-speed clearance for severe faults. The enduring reliability and straightforward application of the ALSTOM IR139-1 have made it a trusted choice for decades, often used as a cost-effective backup or enhancement to more complex digital protection systems, solidifying its value in safeguarding electrical infrastructure.

IR139-1 ALSTOM

Technical Specifications

Main Features and Advantages

The ALSTOM IR139-1 offers a set of distinct advantages rooted in its proven electromechanical technology. Its most significant feature is self-powered operation: the relay requires no external auxiliary power supply. It is energized solely by the current flowing from the Current Transformers, making it inherently fail-safe and operational during main power outages, a critical requirement for protection functions. This design ensures ultimate reliability and simplifies system design by eliminating the need for additional power wiring and supplies.

Robustness and Simplicity: The electromechanical construction of the ALSTOM IR139-1 makes it highly resistant to electrical transients, surges, and electromagnetic interference (EMI), which can sometimes disrupt solid-state or digital relays. This inherent immunity guarantees stable operation in electrically noisy industrial environments. The setting is mechanically adjusted via a simple, calibrated dial, providing a clear and tamper-resistant configuration that does not require software or complex programming tools. This ease of use reduces commissioning time and minimizes the potential for setting errors. The robust mechanical design ensures a long service life with minimal maintenance, making the ALSTOM IR139-1 a “fit-and-forget” component in many protection schemes, renowned for its unwavering performance over decades of service.

Application Field

The ALSTOM IR139-1 finds its primary application in medium-voltage electrical distribution networks where rapid fault clearance is essential. It is extensively used in industrial plants for the protection of feeders, transformers, and large motors. For instance, it can be applied as a high-set instantaneous element to provide fast tripping for severe short-circuit faults on an incoming utility feeder, working in coordination with other time-delayed overcurrent relays. Its earth fault capability makes it suitable for detecting ground faults in resistance-grounded or isolated neutral systems, protecting against insulation failure.

Beyond industrial settings, the ALSTOM IR139-1 is a common sight in utility substations, particularly on distribution feeders where it acts as a reliable and economical primary or backup protection device. It is also ideal for applications in mining, water treatment facilities, and oil and gas installations, where environmental conditions can be demanding, and the simplicity of the ALSTOM IR139-1 is a major benefit. Due to its standalone nature, it is often deployed to retrofit older switchgear or to add a dedicated, high-speed protection layer to specific assets within a broader digital protection scheme, ensuring critical equipment remains protected against catastrophic damage from overcurrent conditions.

IR139-1 ALSTOM

Related Products

IR139-2: A two-phase version of the same relay, providing instantaneous overcurrent protection for two phases in a single unit.

IR140: A Microtrip IDMT (Inverse Definite Minimum Time) overcurrent relay, offering time-delayed protection for coordination with other relays.

IR171: A Microtrip overcurrent and earth fault relay with both instantaneous and IDMT characteristics in a single housing.

IR21: A differential protection relay from the same era, used for protecting transformers and generators.

KCEG 142: A modern GE Multilin digital relay, representing the evolution of protection technology from the electromechanical IR139-1.

VA51: A voltage protection relay from ALSTOM, often used in conjunction with current relays for comprehensive system protection.